The Flyers' defense, not particularly good at its baseline level, will be without Andrej Meszaros for at least a month, GM Paul Holmgren said Friday.

A Ryan Callahan hit injured Meszaros in the Flyers' loss to the New York Rangers on Thursday night.

“We’re hoping it’s about a four-week rehabilitation of the injury," Holmgren said, according to the Philadelphia Inquirer. "It’s a muscle injury in and around the shoulder joint. We just need to strengthen the area and we believe he’ll be out around a month.”

Andreas Lilja will take Meszaros' place with the Flyers (1-3), who play the Florida Panthers on Saturday.

Losing a defenseman is a change of pace for the Flyers—they're without top-line winger Scott Hartnell because of a broken toe and forward Zac Rinaldo because of a skate laceration. Forward Daniel Briere (wrist) has yet to play this season but may return this weekend.

"You're going to need players to play in a short season, a 48-game season like we have. We believe we have depth in our organization," Holmgren said, according to The Associated Press. "We've seen some of our young kids up already playing. We're being tested obviously right now, which is good and bad, but we'd obviously like to get ourselves healthy because we know we're in for a dogfight in what we have left of our schedule."

Each injury makes it more likely that Holmgren makes a major move, as his track record indicates, but nothing appears imminent. Though they're approaching the salary cap, the Flyers are on the short list of teams that could (and would) theoretically sign PK Subban to an offer sheet or swing a trade. The Montreal Canadiens defenseman is still holding out, and no agreement is on the immediate horizon.

To help in the short term, Philadelphia signed veteran winger Mike Knuble to a one-year, $750,000 deal. He'd been a legitimate top-six forward and power-play component until last season, but was benched by the Capitals and is 40 years old.

“He’s played a long time in this league,” Wayne Simmonds told CSN Philly. “He’s a great player, and he’s a great net-front presence, actually, and I think I can learn some things from him. I think he’s going to bring veteran leadership.”

Knuble has played in 1,040 career games with Detroit, Boston, Philadelphia and Washington, and has 274 goals and 540 points. He won a Stanley Cup with Detroit in 1998.

"I'll be ready for anything. I'm pretty realistic that for a guy like me, you're going to be a spot-filler, going to fill some holes at times, and come in and do what's asked of you, play where you need to play," Knuble said. "You're going to go out and try to do your best in that role that night and try to do what you can do. I just need to be ready to move around, probably a lot, and be ready for anything."